argument by Lucretius

2. The soul is made of exceedingly fine atoms and has two connected parts: the
anima distributed throughout the body, which is the cause of sensation, and the
animus in the breast, the central consciousness. The soul is born and grows with the body, and at death it is dissipated like “smoke.”

work of Stahl

...reason that kept a living body from its natural decomposition. Stahl identified this reason with the principle of life, which he sometimes called “natura” (nature) and sometimes “
anima” (soul). Anima functioned with a natural reason (“ratio”), in contrast to logical, critical reasoning (“ratiocinatio”) that the rational soul performed. This...